This invention generally relates to light guide assembly for an illuminated dial. More particularly, this invention relates to a light guide assembly for an illuminated dial that increases light use efficiency.
Conventional illuminated dials utilize a light source such as a light emitting diode (LED) mounted to a circuit board and a light guide device. The light guide device directs light from the mounting location on the circuit board to the surface of the dial. In some applications it is desired to direct light parallel to the surface of the dial to provide the desired aesthetic appearance. Light is therefore directed by way of straight light guide portions connected at a relative angle to each other. The angular connection between straight light guide portions creates an over illuminated point that is not desirable. The over illuminated point or intersection between the straight light guide portions is typically blocked to prevent the over illumination from destroying a desired uniform appearance. For this reason, the angular portion is typically minimized so that the desired uniform lighted surface is available to illuminate more of the gauge.
Blocking light at the intersection points reduces the amount of light available for illuminating the dial gauge. In some instances as much, if not more than 30% of the available light is blocked, thereby reducing the efficiency of the light source and potentially requiring the use of an increased number of light sources, or the use of larger light sources that require more power to obtain the desired illumination.
Accordingly, it is desirable to design and develop a light guide assembly that increases the efficiency of light utilized for illuminating a dial or other instrument device.